Cut the bok choy diagonally into 1/2 inch thick slices, slice mushrooms. If substituting broccoli for bok choy, peel the stalks until no more strings come out, and slice thinly on the diagonal.

Heat the frying pan on high, add 2 tbsp of oil and fry the noodles in small portions until they are golden. Use chopsticks to separate the noodles as they are frying. Remove the noodles.

Add more oil and add the chicken and onion to the pan. Stir-fry until the meat has no redness. Remove from wok or pan.

Cook the rest of the vegetables separately, adding a bit of salt if desired to taste. If desired, add about 1/4 cup of water and cover pan while cooking bok choy, as it doesn't contain much moisture.

Add all the ingredients back into the wok,add the gravy. Mix well. Add green onions at this point if desired, or save them for a garnish. Pour the mixture on top of the noodles. Garnish the chow mein with sesame seeds.